{{$page_output}} is a global variable defined by the Horde_Framework. It is used to format the output of dynamically generated pages.
[http://dev.horde.org/api/master/lib/Core/classes/Horde_PageOutput.html API Documentation]
+++ Page Header
$page_output->header(array(
'title' => _("List")
));
+++ Page Footer
$page_output->footer();
+++ Adding Javascript
++++ Javscript file that lives in an application's {{js/}} directory
// $page_output->addScriptFile($name_of_file_relative_to_base_of_js_directory, $app_name);
// Example, for Horde:
$page_output->addScriptFile('login.js', 'horde');
++++ External Javascript file
// The file MUST be web accessible.
$page_output->addScriptFile(
new Horde_Script_File_External($relative_URI_to_JS_file)
);
++++ Adding inline Javascript code
$page_output->addInlineScript(
$javascript_code,
true
);